Cerebrospinal fluid from HAM/TSP patients with rapid evolution affects mitochondrial DNA transcription and structure in human glioblastoma cell lines

Human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a progressive neurodegenerative disease impacting motor and sensorial functions. While the cerebrospinal fluid (CSF) alterations have been used to identify biomarkers for this disease, the effects of HTLV-1 CSF on neural cells remain unexplored. Herein, we investigated the impact of CSF from HTLV-1 infected patients on glioblastoma cell lines. CSF samples were obtained from HTLV-1 asymptomatic carriers (HAC) (n=13), and HAM/TSP patients (n=21) categorized according to the speed of disease progression: very slow (HAMvs), typical (HAMt), and rapid (HAMr). RNA sequencing of glioblastoma cells treated with HTLV-1 CSF revealed notable gene expression changes, particularly with HAMr CSF, which caused significant downregulation of mitochondrial DNA transcripts. Confocal microscopy showed phenotypical changes in the mitochondrial network: astrocytes exposed to HAMr CSF exhibited a less complex mitochondrial network compared to CSF from other patient groups. It is characterized by reduced mitochondrial branching, fewer junctions per branch length, and slightly increased branch diameter. Compared to untreated cells, HTLV+ CSF disturbed mitochondrial metabolism. However, these changes are limited at the metabolic level and do not appear to vary significantly with HTLV donor status. In conclusion, our findings suggest that HTLV+ CSF induces mitochondrial reorganization in glioblastoma cells, potentially helping to compensate for the stress caused by the CSF exposure. Overall design: Bulk RNA-seq profiling of U87-MG cells incubated for 6 hours and 24 hours with cerebrospinal fluid from HAM/TSP patients with different speed of disease progression.

人类T淋巴细胞病毒1型（Human T-lymphotropic virus 1, HTLV-1）相关脊髓病/热带痉挛性截瘫（HAM/TSP）是一种累及运动与感觉功能的进行性神经退行性疾病。尽管脑脊液（cerebrospinal fluid, CSF）的异常变化已被用于该疾病的生物标志物鉴定，但HTLV-1感染患者的脑脊液对神经细胞的影响仍未被探明。本研究探究了HTLV-1感染患者的脑脊液对胶质母细胞瘤（glioblastoma）细胞系的影响。我们收集了HTLV-1无症状携带者（HAC）的脑脊液样本（n=13），以及根据疾病进展速度分类的21例HAM/TSP患者脑脊液样本：极慢进展组（HAMvs）、典型进展组（HAMt）与快速进展组（HAMr）。对经HTLV-1相关脑脊液处理的胶质母细胞瘤细胞进行RNA测序后，发现存在显著的基因表达改变，其中以快速进展组脑脊液（HAMr CSF）诱导的改变最为突出，该组样本可显著下调线粒体DNA转录本的表达。共聚焦显微镜（confocal microscopy）观察显示线粒体网络出现表型改变：与其他患者组脑脊液处理组相比，暴露于HAMr CSF的星形胶质细胞（astrocyte）的线粒体网络复杂度更低，具体表现为线粒体分支减少、单位分支长度的连接点更少，且分支直径略有增加。与未处理的细胞相比，HTLV阳性脑脊液会干扰线粒体代谢，但这类改变仅局限于代谢层面，且未随HTLV供体状态出现显著差异。综上，本研究结果表明HTLV阳性脑脊液可诱导胶质母细胞瘤细胞发生线粒体重构，或可代偿脑脊液暴露所引发的应激压力。总体实验设计：将U87-MG细胞与不同疾病进展速度的HAM/TSP患者脑脊液分别孵育6小时与24小时后，进行批量RNA测序（Bulk RNA-seq）分析。